This invention is concerned with component supply means especially suitable for electrical or electronic components of a variety of shapes and sizes, for example so-called flat packs, S.O. style transistors, leadless chip carriers, dual in line packages, melf-type components and the like, as well as so-called "chips".
In the manufacture of electrical or electronic equipment it is necessary to assemble a plurality of components on a suitable substrate, for example a printed circuit board. A number of systems have been proposed for handling the components to be placed on a substrate and many of these have proposed the use of pick-up heads having a suitable tool by which a component may be picked up. The tools have been of various types, depending on the components to be handled to some extent; for example the tools may mechanically grip the components or may use suction or a magnetic system to retain a component on the tool of the pick-up head when the component is removed from a suitable component supply means for delivery elsewhere for example to a suitable placement position where the component may be placed on a substrate e.g. a printed circuit board.
In the mounting of components on substrates especially placement of electrical or electronic components on printed circuit boards, in particular using surface mounting techniques, it is important to present a variety of components for use rapidly. Components are conveniently supplied in appropriately constructed magazines, many of which are already known. One known type of magazine which is especially convenient for the supply of components to a component placement machine for use in surface mounting is known as a tape feeder: in this type of magazine, components are housed in pockets equally spaced along a tape which is wound around a suitable reel: whenever it is desired to use a component from such a magazine the tape is indexed through a feed step (equivalent to the spacing between one of the pockets and the next adjacent pocket) to present a component at a transfer position of the magazine where the component may be transferred to other operating instrumentalities, for example a pick-up head of a component placement machine.
In order to minimise breaks in production it is important that when a supply of components in a magazine is exhausted, the supply can readily be replenished. For many magazines this is most readily accomplished by removing a magazine and replacing it by a new magazine; even using tape feeders, where the reels can be replaced, the time necessary to remove an old reel, replace it by a new reel and thread the tape correctly through the feeding instrumentalities of the magazine is time consuming and often more easily accomplished when the magazine is not in place on a component supply means. Thus even tape feeders may be more appropriately exchanged than reloaded in situ on component supply means. Furthermore, should it be desired to change components to be supplied for a particular purpose, for example when it is wished to place components on a printed circuit board of different design using some different components, it may be necessary to exchange a number of magazines to provide appropriate components, although preferably the component supply means mounts a sufficient number of magazines to provide components for a number of different substrates for example a variety of relatively simple printed circuit boards as well as one or more complex substrates. Indeed, where a sufficiently substantial change in the purpose for which components are to be supplied is necessary, it may in some cases be preferable to exchange a whole component supply means, removing the original supply means and replacing it by a similar supply means having magazines supplying a whole range of different components.
In some applications, for example supply of components to a placement machine for surface mounting, for most efficient operation it is important that the components be presented for transfer at a precise location of a transfer station for transfer to further operating instrumentalities, for example the pick-up head of a component placement machine. While it is theoretically possible to manufacture a component supply means including exchangeable magazines to such precise tolerances that the necessary precision is achieved in the manufacture of the component supply means, the cost of such accurate engineering on the scale necessary would be enormous: for example, a component supply means of a component placement machine for surface mounting may comprise 150 magazines and not only would the carrier on which the magazines are to be mounted need to be constructed very accurately but each of the magazines would need to be constructed with the same degree of accuracy.
One of the various objects of the present invention is to provide an improved component supply means, especially an improved component supply means for supplying electrical or electronic components.
Another object of the invention is to provide an improved component placement machine.